I was heading out yesterday to cycle to the supermarket, doing my "pre-ride checks", and I noted the back wheel had a great big kink in it. Really hard to see by eye, but as it spun it did a big sideways 'pulse'.
I'd broken a spoke and the wheel was out of true.

Now, wheelbuilding is something I don't know how to do well, so I took it to the bike shop (who are booked solid until next week) - and left it with them until they get a clear slot. I'd rather leave it with them than have it sit in the garage with no possibility of being fixed early. Whilst there, they're going to give it a pre-autumn once over (it's my commute bike, as opposed to my good bike). It saves me a job.

I was surprised at how hard it was to detect the broken spoke without physically pushing the spoke - there was no 'bang' as it broke, and the wobble on the wheel was sideways, and so didn't translate into a regular 'bump' I could feel in the saddle.